Maple 9 Learning Guide - Maplesoft

38 • Chapter 2: Mathematics with Maple: The Basics> combine((x^a)^2, power);(2 a)xThe map CommandThis command is useful when working with lists, sets, or arrays. It providesa means for working with multiple solutions or for applying anoperation to each element of an array.The map command applies a command to each element of a datastructure or expression. While it is possible to write program structuressuch as loops to accomplish these tasks, you should not underestimate theconvenience and power of the map command. The map command is one ofthe most useful commands in Maple.> map( f, [a,b,c] );[f(a), f(b), f(c)]> data_list := [0, Pi/2, 3*Pi/2, 2*Pi];data_list := [0, 1 2 π, 3 π, 2 π]2> map(sin, data_list);[0, 1, −1, 0]If you give the map command more than two arguments, Maple passesthe last argument(s) to the initial command.> map( f, [a,b,c], x, y );[f(a, x, y), f(b, x, y), f(c, x, y)]For example, to differentiate each item in a list with respect to x, youcan use the following commands.> fcn_list := [sin(x),ln(x),x^2];fcn_list := [sin(x), ln(x), x 2 ]